One Last Time
by HesterValentine
Summary: Dean is brought face-to-face with a brutal future when left alone in the bunker in this Destiel One Shot. [Based off a dream after spending too long on Tumblr. Could potentially be expanded if there's enough interest. Review with Reactions or Requests]


_Author's Note : Please review - I might use this as a collection of one shots, but it depends on how well this does. Usually I write anime fics using teenagers. This is much harder! But I'm looking to expand what I can write so if you want to request anything, drop me a message and I'll put it on a list._

One Last Time

Something shattered. Dean looked up sharply, butter knife hovering over the sandwich that he glanced back at longingly. There was a following crash and his lunch was abandoned in favour for the gun he swept up off the table as he barrelled into the hall. His back hit the wall by the entrance to the main room of the bunker. Dean exhaled slowly, listening to the movement somewhere ahead of him, and checked his clip instinctively. There was another bang. Gritting his teeth, he swung round the doorframe, the gun swinging up ahead of him.

"Jesus Christ, Cas." The gun lowered and he sighed, shoving it back in his waistband. "What the hell are you…" It took him a moment to notice the mug smashed on the floor, the over-turned chair, the stains up the back of the torn trench coat as the man leant heavily on the table of the war room. Dean frowned.

"Cas? You okay, man?" The angel didn't answer him. He didn't seem to hear him at all. Dean reached out to touch his shoulder and Castiel started, swinging round to face him. His face was battered, bruising blossoming across his temple, his jawline, down his neck. There was blood in his hair and crusting over one eyes. His lip was broken and swelling, blood drying in streaks down his chin. Alarmed, Dean reached out but Castiel held up his hand, steadying himself on the table.

"Dean." His voice was hoarser than usual. "Why are you here?"

"Cas, what happened?" He asked urgently. "Where's Sam?" Castiel shook his head and laughed hollowly.

"Cas, talk to me." The angel looked up at him and Dean had never seen his eyes like that – they were hollow. Blank. He almost took a step back. Almost.

"You're not supposed to be here," Castiel said, so quietly that Dean almost missed it. His eyebrows shot up and he grabbed the shoulder of the dirty trench coat.

"What are you talking about?" He demanded. "Cas, you guys went out for _groceries_. What…" He stopped suddenly. He stared at Castiel, who looked resolutely past him, and reached down to flip the coat aside. The front of the shirt was sodden with crimson, a vicious tear across his abdomen. The blood was still soaking into the white fabric and the dark pants. Castiel sighed shakily and tipped sideways, forcing the hunter to catch him. Dean swore and pressed his hand against the wound, blood pulsing over his fingers, dripping, streaming, but the wound was so long – he didn't know where to apply pressure. He looked around frantically and attempted to pull Castiel towards a chair. The angel gave a short cry of pain, stunning him into stillness, and he glanced down at the leg that was twisted at a horrifying angle.

"Okay, okay," Dean muttered, attempting to lean Cas back against the table, "We won't move." He started to pull off his shirt, balling it up to press it against the wound as Castiel breathed shallowly, gripping the side of the table with white knuckles.

"Dammit, Cas, what happened? Who did this? _Where's Sam?_ " Castiel tilted his head and looked at him, expression unreadable. Dean jerked his head away automatically as the angel's fingers brushed his forehead. Castiel paused.

"I don't understand," the angel muttered.

"Welcome to the club," Dean said furiously, trying to pretend he couldn't feel the shirt becoming sodden under his fingers. "Cas, can't you, you know, heal yourself?" He got a small shake of his head in response. He didn't ask. He could feel the angel shaking under his grip. Castiel was weak, weaker than he'd seen him in a long time. When his good leg gave out, Dean half carried him to the nearest chair, trying to ignore how surprisingly light he was. Something was very wrong with Castiel but he couldn't put his finger on it.

"You're going to be fine, Cas, you're going to be fine," he murmured, almost to himself, "Because you're not going to do this to me again, you understand?"

"Look who's talking," Castiel mumbled, which sounded a lot like sass but his eyes were almost completely closed. Dean patted his face sharply and tipped his head to look at him, gripping the back of his neck to steady him in the chair.

"Whoa, whoa, no, you don't. Stay awake, Cas. Talk to me. Tell me what happened." There was too much blood. Angels shouldn't bleed like this. It had soaked through his shirt now, pooling around his fingers, staining his skin.

"You happened, you ass." Dean looked up at Castiel, shocked, and the angel's eyes were watching him closely. "What did you think I was going to do?"

"You've lost me, Cas," the hunter said, rearranging the shirt and glancing around for anything within arm's reach that could help. "Let's start at the beginning, when you left."

"I didn't leave," Castiel sighed, eyes flickering closed. "You did." Dean stared at him for a moment. He was really pale, almost gaunt.

"What? No, Cas, I'm here, right here." Dean used both hands to press down on the wound, making the angel wince. "You went on a supply run with Sam, remember?" Castiel's breathing was ragged and his head lolled worryingly.

"I know you, you told me not to." His voice was barely a whisper. "But I had to try. After what they did."

"Cas, who? Who did this?" He shook him slightly. "Do they have Sam?" Castiel laughed again, but there was no humour in it, and this time there was a wetness behind it that Dean had heard before. He looked up at the blood that dribbled out between Castiel's lips, parted as he tried to breathe. The angel was bleeding into his lungs. His hand moved to the angel's chest and felt the bones shift under his skin with each breath, broken ribs crunching against each other painfully. His jaw worked as his mind raced. In a small pause between thoughts, he realised Castiel's tie was gone. He could have used that somehow. Sam would know what to do. He felt cold. He couldn't help. He needed to find Sam. He needed to save Cas. What was he going to do?

He jumped as a hand curled around his t-shirt and the angel pulled him down, lips meeting clumsily. He was too surprised to react to the sudden soft warmth of Castiel's mouth on his, to the goose bumps on his skin, the heat rising in his cheeks, until Castiel pulled back, brow furrowed. His bright blue eyes were swimming as they searched Dean's, his hand seeking out the one resting on his chest.

What the hell was _that?_

"C-Cas?" The angel was frowning as his thumb traced across Dean's fingers. Dean stared at Castiel, frozen.

"Oh," the angel breathed, lifting his hand to squint at it. "I came back too far. Much too far."

"Came… came back?" He watched Castiel study his hand intensely, eyes wide. "You time-travelled?"

"It was supposed to be a month. I over-shot. By years." He coughed, painfully, and Dean caught him as he curled into himself. Each coughed sprayed blood over the floor and Castiel shuddered. Dean held him, his brain working furiously.

"Cas, you gotta give me more than that," he said desperately. Castiel rested his head on Dean's shoulder, too weak to pull himself upright.

"I lost someone. And I did something stupid." He chuckled and winced. "You would have called it going full Winchester."

"Dude, never go full Winchester," Dean forced out but his attempt at levity didn't help.

"You told me there was too many angels to take on by myself but I didn't listen," Castiel whispered. His voice was getting quieter.

"Well, that clearly never changes." Angels. Of course it was angels. Dean felt a surge of rage, cut off by the soft voice:

"I didn't know what else to do."

"Why didn't you take me with you?" Dean demanded but Castiel curled, hacking blood down his t-shirt. Crimson was running off the chair now, dripping into a dark puddle. The angel was starting to slip off the chair and Dean carefully adjusted his grip to slide him onto the floor, afraid he was going fall. The blood smeared as he propped Castiel up against him, his hand still pressed against the wound, even though he knew it was pointless now. He heard a door slam open and Sam call him, too casually. He shouted for his brother, hearing the panic in his own voice. Castiel's breathing was becoming more superficial every second.

"Dean!" Sam's gun was out and he slid to a stop. His eyes flicked down to Castiel, bloodied and broken, and then he span, the gun coming up to stop Castiel, perfectly fine, in his tracks.

"Sam?" The standing Castiel said, confused, and then he saw himself, shuddering in Dean's arms. His eyes widened.

"Asmodeus?" Sam snarled.

"What, Sam, no!" Dean yelled. His brother cocked his head.

"Shifter?"

"Sam, put your friggin' gun down and _help me!"_ Something broke in his voice. They both looked at Dean, whose grip tightened on the sodden shirt as it leaked rivulets of red over his hand. Sam darted away, unquestioning.

"That's me," Castiel said, sounding slightly perturbed. In his arms, the angel gave a juddering sigh and his eyes cracked open. It was bizarre. Dean looked between them as they stared at each other. He could see what it was now, what was wrong with this future Cas. Everything about him had been dulled. There was no fight in him. This wasn't the Castiel that would stand for hours to watch branches weave in the wind, or the dance of the bees, or the colours of flowers along the flow of the river. This wasn't the Castiel enamoured with the beauty of creation.

This Castiel had given up.

"Hello," the broken Castiel said and everybody heard it in his voice.

"Cas," Dean said, looking at his Castiel pleadingly, "Can you heal him?" Nodding, he started forward when the angel from the future shook his head as violently as he could manage.

"What are you doing?" Dean demanded.

"He doesn't want to be healed," Castiel said simply.

"So?! He's _you!_ "

"I chose to believe that there must be a reason for him, for me, to not want-"

"Cas, your reasoning doesn't have the best track record," Dean snapped. "I don't give a shit what future you wants, I am _not_ losing you again!"

"Dean…"

"I remember this now," a soft voice said and they both looked down at him. Slowly he lifted Dean's hand away from his bloodied stomach with all the strength he could muster – which as barely anything. Dean let him, afraid any resistance would hurt him more, as Sam ran back into the room, forcing open a first aid pack and up-ending it on the table. Future Castiel didn't let go of Dean's hand as he tilted his head to stare, blue eyes clouding very slowly.

"And so did you. That's why you told me not to go," he murmured, and touched Dean's face with a sad smile. "I'm sorry, Dean. I'll never listen." Dean stared back at him and felt the heat in his face even as his heart knotted inside him. He'd started to cry silently at some point. He couldn't do this again. He couldn't. He gripped Castiel tight and told him he was going to be okay. He had to be okay. Sam was going to be back in a second and they'd patch him up and he'd be fine and he could go back to whenever he came from and then his own Dean would kick his feathered ass across the bunker and then…

And then there was nothing.

He stared at the floor, frozen.

"Dean," Castiel said gently.

"What… what did he…"

"He went back, Dean."

"But he'll die," Dean said blankly, staring at the pool of blood as he staggered to his feet.

"I think," Sam said slowly, "That was the point."

"You shut your mouth," Dean snapped at his brother and then rounded on Castiel. "What the _hell_ was that about?"

"I don't know," the angel replied honestly.

"He was _you,_ Cas! If anyone can…" Dean paused and looked down at his hand, stained with blood.

"Dean, what did he say?" Sam asked, throwing him a towel.

"That he'd lost someone. And basically gone all Leroy Jenkins on an angel army." He glared at Castiel. "I swear to god I'll kick your feathered ass if you _ever_ pull something like that on me!"

"But you just-"

"Shut up, Cas."

"So why did he come here?" Sam mused, leaning back against the table. Dean tried to wipe the blood off his hand angrily and, his fist hidden within its folds, unclenched his fingers.

The two rings shifted in his palm, clinking against each other gently. One shone bright and silver, just as broad, just as worn, with an etching of: ' _I need you'._ The other was dull and heavy as iron, and he could just make out the rough, worn etching on the inside: ' _All of it, for you'._ Both were bloodied, but the second had dried a long time ago, each letter stained dark.

"To say goodbye," he murmured, "One last time."


End file.
